Use s3 file system to export query results

Hello,
I am using hue helm with Hue version 4.11.0 on EKS. I assigned one service account that can assume an AWS IAM role. Then I configured hue to use s3 bucket as follow:

[filebrowser]
  remote_storage_home=s3a://${hue_home_s3_bucket}
[aws]
  [[aws_accounts]]
    allow_environment_credentials=yes
    region=eu-central-1
    calling_format=boto.s3.connection.OrdinaryCallingFormat

I was hoping it would work. but when I try to export query results, then it gives a strange error:
Expecting value: line 1 column 1 (char 0)

In the container logs, it gives an error about webhdfs:

hadoop.fs.exceptions.WebHdfsException: HTTPConnectionPool(host=‘localhost’, port=50070): Max retries exceeded with url: /webhdfs/v1/user/test?user.name=hue&doas=test&op=GETFILESTATUS (Caused by NewConnectionError(’<urllib3.connection.HTTPConnection object at 0x7f62bee42fa0>: Failed to establish a new connection: [Errno 111] Connection refused’))

I am wondering how can I make it working. Thanks